1. Field of the Invention
The present invention generally relates to printing wiring patterns on greensheets and more particularly to an improved process for personalizing green sheets that utilizes X-ray printing.
2. Description of the Related Art
Large ceramic sheets that are used in the electronic industry are referred to as xe2x80x9cgreensheetsxe2x80x9d. Such greensheets are used as a platform (e.g., board) to form connections between prefabricated integrated circuit chips. Such greensheets normally contain standard wiring patterns; However these wiring patterns can be customized (personalized) to accommodate the specific needs of given designs.
Traditionally, the personalization of greensheets was performed using screen printing techniques. However, screen printing techniques suffer from a number of disadvantages. For example, the masks used to perform the screen printing have a very limited life and screen printing has limited resolution.
Thus, as the line widths and spacings of circuit patterns on ceramic packages continue to decrease, the limits of traditional screen printing techniques are being approached. To meet the ever more aggressive design criteria, it is desirable to continue tightening the ground rules of the package while maintaining the speed and relative simplicity of screen printing. The invention described below resolves these problems via the utilization of X-ray lithographic methods and composite photo resists.
In view of the foregoing and other problems, disadvantages, and drawbacks of the conventional greensheet personalization processes, the present invention has been devised, and it is an object of the present invention to provide a structure and method for X-ray greensheet printing.
In order to attain the object(s) suggested above, there is provided, according to one aspect of the invention, a method which forms a conductive pattern on a ceramic sheet and deposits a photosensitive conductive material on a carrier. The invention then exposes a pattern of x-ray energy on the material and sinters the carrier and the material to the ceramic sheet such that only the conductive pattern of the material remains on the ceramic sheet. After the exposing, the invention develops the material and rinses the material to remove portions of the material patterned by the exposing so that the conductive pattern matches the pattern of x-ray energy. The exposing process exposes the pattern of x-ray energy through a non-contact mask. The sintering process removes the carrier and allows only the material to remain on the ceramic sheet. The material is a composite of a metal and a photosensitive agent which includes one of gold, nickel, molybdenum, and copper.
The invention further includes a wiring structure which has a photosensitive agent that is an exposed and developed photosensitive agent. The material of the structure is one of gold, nickel, molybdenum, and copper. The wiring structure includes a ceramic substrate which is a ceramic greensheet. The invention also contains a photosensitive agent which is one of polymethyl methacrylate and polybutene-1 sulfone.